Archives Séminaires 2019-2020

Séminaire exceptionnel

Séminaire IPAG de Ismael Perez-Fournon (Instituto de Astrofísica de Canarias), mercredi 5 février 2020, 11h00, IRAM seminar room

Sloan Digital Sky Survey (SDSS) imaging and spectroscopy have been crucial to identify many types of gravitational lenses up to high redshifts. I will present recent results on the rest-frame UV properties of gravitationally lensed Lyman alpha emitters (LAE) from the BELLS GALLERY survey (Shu et al. 2016a,b, Marques-Chaves et al. 2017, Cornachione et al. 2018, Marques-Chaves et al. 2019) based on the combination of SDSS spectroscopy (for source selection) with HST, William Herschel Telescope (…)

Séminaire

Séminaire IPAG de Louis Amard (Exeter), jeudi 6 février 2020 à 11h00, IPAG seminar room

The angular momentum of young low-mass stars is a long-standing problem that has, so far, not been solved. Why is the Sun spinning so slowly while its initial contraction should have left him with a rotation period smaller than a day ? Or in other words, how did the Sun lost all its angular momentum since its formation ? The answer likely involves several physical processes all along the life of the star.
In this talk, I aim at presenting you the most recent results regarding the (…)

Séminaire IPAG de Yves Marrocchi (Centre de Recherches Pétrographiques et Géochimiques - Nancy), jeudi 13 février 2020, 11h00, IPAG seminar room

Chondrites are leftover solids from the evolution of the solar protoplanetary disk 4.56 Gyr ago. They are composed of varying proportions of four main components : refractory inclusions, chondrules, Fe-Ni metal and matrix material. These materials were subsequently accreted together to form the asteroidal parent bodies that represent the source of unequilibrated meteorites. Refractory inclusions are high temperature assemblages composed of crystalline silicates and oxides rich in calcium and (…)

Séminaire IPAG de Coralie Neiner (LESIA), jeudi 20 février 2020, 11h00, IPAG seminar room

In many domains of astrophysics, the study of magnetism and polarized light has become a new and essential tool. This has however never been done in the UV as it requires to go into space. I will present recent R&D work on UV polarimeters and current studies of space mission projects equipped with a high-resolution UV spectropolarimeter, such as Pollux for LUVOIR, Arago, and CASSTOR.

Séminaire IPAG de Jan Orkisz (Chalmers), jeudi 11 juin 2020, 11h00, online seminar

In order to give birth to new stars, the matter of the interstellar medium has to progressively accumulate, go through denser and denser phases of ionised, atomic or molecular gas, forming clouds, clumps and cores in which eventually the pressure and density reach values high enough for nuclear fusion to occur.
During this evolution, the motions of this complex environment are driven by gravity, disrupted by stellar feedback, influenced by the heating and cooling of the gas... At all stages (…)

Séminaire IPAG de Aurélien Wyttenbach (IPAG), jeudi 18 juin 2020, 11h00, online seminar

Observations of exoplanet atmospheres allow us to characterize several of these remote worlds. Indeed, the measurement of planetary spectra are rich in information about these planets’ physical and chemical conditions.
The parameter space explored by exoplanetary atmospheres is much larger than the one in the Solar system. This allow us to explore complicated phenomenons, such as radiative transfer, atmospheric circulation, atmospheric escape, chemical (dis)equilibrium, cloud formation, (…)